Abstract

Studies of the spontaneous ignition of mixtures of aluminium trimethyl and oxygen show that the ignition boundary is defined by the expression: l/pAl2Me6 = A —B/pO2 where pAl2Me6are the partial pressures of the reactants. It is found that the values of A and B are only slightly affected by temperature and by added inert gases. The main products formed during ignition are hydrogen, carbon monoxide, methane, acetylene and a complex grey aluminium-containing solid. The kinetic and analytical findings can in general be accounted for in terms of an isothermal free radical chain mechanism. This predicts correctly the effects of reactant pressures, of temperature and of helium, but fails to account quantitatively for the influence of surface: volume ratio. As the ignition limit is approached from the slow combustion region, the branching reactions Me2AlOO. + Al2Me6 -> Me2AlOOMe + 2Me2Al. + Me., Me2AlOOMe -> Me2AlO. + .OMe, Me2AlO. + Al2Me6 -> Me2AlOMe + 2Me2Al. + Me., appear to become important and to lead to ignition.

Footnotes

This text was harvested from a scanned image of the original document using optical character recognition (OCR) software. As such, it may contain errors. Please contact the Royal Society if you find an error you would like to see corrected. Mathematical notations produced through Infty OCR.